#通过SQLAlchemy对数据库进行增删改查# 想要操作数据库 先要打开数据库连接from create_table import engine# 创建会话 - 打开数据库连接from sqlalchemy.orm import sessionmaker# 创建会话窗口Session = sessionmaker(engine)# 打开会话窗口db_session = Session()from create_table import Useruser_obj = User(name='XJ')# 通过db_session(已经打开的会话窗口)db_session.add(user_obj)# 提交执行操作db_session.commit()# 关闭会话db_session.close()# 增加批量数据from create_table import Userdb_session.add_all([    User(name='XJ1'),    User(name='XJ2'),    User(name='XJ3')])db_session.commit()db_session.close()

# 更新修改数据from sqlalchemy.orm import sessionmakerfrom create_table import engine,UserSession = sessionmaker(engine)db_session = Session()# 1.修改数据# SQL语句# update User set 'name' = '徐建' where id = 2user = db_session.query(User).filter(User.id==2).update({
       'name':'徐建'})db_session.commit()db_session.close()

# 删除数据from sqlalchemy.orm import sessionmakerfrom create_table import engine, UserSession = sessionmaker(engine)db_session = Session()# 1.删除# SQL语句# delete from user where id =2user = db_session.query(User).filter(User.id==2).delete()print(user)db_session.commit()db_session.close()# 2.删除多条res = db_session.query(User).filter(User.name=='XJ2').delete()db_session.commit()db_session.close()print(res)

# 查询# 会话窗口from sqlalchemy.orm import sessionmakerfrom create_table import engineSession = sessionmaker(engine)db_session = Session()from create_table import User# 查询所有# SQL语句# select * from tableuser_list = db_session.query(User).all()for row in user_list:    print(row.id, row.name)# 查询一个user = db_session.query(User).first()print(user.name)# 带条件的查询user_list = db_session.query(User).filter(User.id==2).all()print(user_list[0].name)user = db_session.query(User).filter_by(id=4).first()print(user.id, user.name)user_list = db_session.query(User).filter(User.id>=2).all()for row in user_list:    print(row.id, row.name)db_session.close()